One of the major causes of death in the United States is heart disease produced by atherosclerosis. In atherosclerosis, a plaque forms in the arteries which may involve only a segmental portion of the artery or can involve its entire circumference. This plaque is a "putty-like" or rock-hard material which, if allowed to accumulate, can completely occlude the artery. Also, the plaque can become dislodged from the artery wall and thereby serve as an embolus, or pieces of it may break off and emoblize. If complete blockage occurs, and the individual survives, sometimes small new vessels recanalize the area, but the ability of these small vessels to supply any appreciable volume of blood beyond the area of blockage is doubtful.
Coronary atherosclerotic narrowing or occlusion has been corrected in recent years most frequently by revascularization of the myocardium. This bypass surgery has become one of the most common surgical procedures performed in the United States. However, the exorbitant cost of myocardial bypass and the associated one to two week morbidity associated with such procedure has led to a procedure termed angioplasty in which an inflatable "balloon" at the end of a catheter is introduced at a selected point in the vascular system and passed into the coronary artery to the site of the occlusion and the plaque compressed by inflating the balloon. Angioplasty, however, is limited in scope of its use because of the variability and the texture of the atherosclerotic plaques and in the inherent limitations of the balloon itself. Moreover, angioplasty is not viewed as a permanent treatment and can result in complications such as artery blow-out, distal emboli spasm, etc.
Development of laser technology for treatment of atherosclerotic plaques is now being conducted, but such a technique, even if successfully developed, has significant limitations.
In a population where average age continues to increase, with a corresponding increase in atherosclerotic heart disease, there is an urgent need for an inexpensive, efficient, safe and effective means for the treatment of atherosclerosis. This urgent need is dictated by the fact that approximately one-fourth of those with atherosclerotic heart disease have as a first symptom sudden death, and each year in the United States alone a million people are diagnosed as having atherosclerotic heart disease. Moreover, a relatively small percentage of those affected with atherosclerotic heart disease are treatable surgically, and there is no indication that there will ever be developed any effective, preventative, pharmacologic treatment of atherosclerotic heart disease.
There is, therefore, a definite and almost urgent need for any technique or device that could produce percutaneous transluminal elimination of atherosclertoc plaques.